Cefsharp IgnoreCertificateErrors after Cef is initialized - wpf

Question

I'm using Cefsharp.WPF in a plugin that runs inside a program which is already using Cefsharp 57.0.0 internally. The recommendation from the main developer is to use this exact version to avoid conflicts. As the main program already has initialised Cef, there's no need to call Cef.Initialize() in the plugin and Cef.IsInitialized returns true too. This means calling Cef.Initialize() throws an exception as expected. The other thing to note is that when shipping the plugin files, I don't need to include Cefsharp dlls and files. I can just create a new ChromiumWebBrowser in my plugin and everything has been working fine until recently.
My plugin has been loading Google maps in a ChromiumWebBrowser. But from about a week ago this request returns ERR_Aborted. Upon investigating I found that setting IgnoreCertificateErrors to true fixes this issue.
I can set my own settings in a test standalone WPF app with Cef 57.0.0 as I initialise Cef myself. So this code loads Google maps fine in my standalone test WPF app:
ChromiumWebBrowser t;
public MainWindow()
{
InitializeComponent();
var settings = new CefSettings();
settings.IgnoreCertificateErrors = true;
//settings.CefCommandLineArgs.Add("ignore-certificate-errors", string.Empty);
Cef.Initialize(settings);
t = new ChromiumWebBrowser();
t.IsBrowserInitializedChanged += ChromiumWebBrowser_IsBrowserInitializedChanged;
g.Children.Add(t);
}
private void ChromiumWebBrowser_IsBrowserInitializedChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (t.IsBrowserInitialized)
{
t.Load("https://www.google.com.au/maps/");
}
}
But in my plugin, I can only set the RequestHandler of the browser instance with a custom implementation of IRequestHandler and implement OnCertificateError. Doing this, I encounter a weird behaviour where Google maps loads but there are some resources broken (not loaded) and seems like some Javascript codes are not running properly also.
Here's the full implementation of IRequestHandler:
public class ChromiumRequestHandler : IRequestHandler
{
public bool GetAuthCredentials(IWebBrowser browserControl, IBrowser browser, IFrame frame, bool isProxy, string host, int port, string realm, string scheme, IAuthCallback callback)
{
return false;
}
public IResponseFilter GetResourceResponseFilter(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response)
{
return null;
}
public bool OnBeforeBrowse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, bool isRedirect)
{
return false;
}
public CefReturnValue OnBeforeResourceLoad(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IRequestCallback callback)
{
callback.Continue(true);
return CefReturnValue.Continue;
}
public bool OnCertificateError(IWebBrowser browserControl, IBrowser browser, CefErrorCode errorCode, string requestUrl, ISslInfo sslInfo, IRequestCallback callback)
{
if (!callback.IsDisposed)
{
using (callback)
{
callback.Continue(true);
return true;
}
}
return false;
}
public bool OnOpenUrlFromTab(IWebBrowser browserControl, IBrowser browser, IFrame frame, string targetUrl, WindowOpenDisposition targetDisposition, bool userGesture)
{
return false;
}
public void OnPluginCrashed(IWebBrowser browserControl, IBrowser browser, string pluginPath)
{
}
public bool OnProtocolExecution(IWebBrowser browserControl, IBrowser browser, string url)
{
return false;
}
public bool OnQuotaRequest(IWebBrowser browserControl, IBrowser browser, string originUrl, long newSize, IRequestCallback callback)
{
return false;
}
public void OnRenderProcessTerminated(IWebBrowser browserControl, IBrowser browser, CefTerminationStatus status)
{
}
public void OnRenderViewReady(IWebBrowser browserControl, IBrowser browser)
{
}
public void OnResourceLoadComplete(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response, UrlRequestStatus status, long receivedContentLength)
{
}
public void OnResourceRedirect(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response, ref string newUrl)
{
}
public bool OnResourceResponse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response)
{
return false;
}
public bool OnSelectClientCertificate(IWebBrowser browserControl, IBrowser browser, bool isProxy, string host, int port, X509Certificate2Collection certificates, ISelectClientCertificateCallback callback)
{
return false;
}
}
I know using a more up-to-date version of Cefsharp will fix the issue but I MUST use this specific version (57.0.0). My question is how can I implement the IRequestHandler to exactly work as if I have set CefSettings.IgnoreCertificateErrors to true?
When I step through the code, the following methods in my custom implementation get called:
OnRenderViewReady
OnBeforeBrowse
OnBeforeResourceLoad
OnCertificateError
GetResourceResponseFilter
OnResourceResponse
OnResourceLoadComplete